Talk:INES Mapper 028: Difference between revisions
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Are both the inner and outer PRG regs always used in PRG swaps? --[[User:Zepper|Zepper]] ([[User talk:Zepper|talk]]) 18:44, 21 September 2013 (MDT) | Are both the inner and outer PRG regs always used in PRG swaps? --[[User:Zepper|Zepper]] ([[User talk:Zepper|talk]]) 18:44, 21 September 2013 (MDT) | ||
:Both registers are used to form the final 16K bank number unless you're in P=G=0 mode, in which case only the outer bank is used. But if you're just switching banks within one game, you're probably writing only to the inner PRG register. Let me make an analogy to a possibly more familiar mapper, [[MMC1]]: Consider the inner PRG register like $E000 and the outer like bit 4 of $A000 on SUROM/SXROM. --[[User:Tepples|Tepples]] ([[User talk:Tepples|talk]]) 12:57, 22 September 2013 (MDT) | :Both registers are used to form the final 16K bank number unless you're in P=G=0 mode, in which case only the outer bank is used. But if you're just switching banks within one game, you're probably writing only to the inner PRG register. Let me make an analogy to a possibly more familiar mapper, [[MMC1]]: Consider the inner PRG register like $E000 and the outer like bit 4 of $A000 on SUROM/SXROM. --[[User:Tepples|Tepples]] ([[User talk:Tepples|talk]]) 12:57, 22 September 2013 (MDT) | ||
Yes, but there's something weird for me. While the PRG diagram shows $8000-$BFFF to use R:01, _and_ $C000-$FFFF to use R:81, I think such PRG bank selection would be _separated_. Later, there's an info regarding '''ORing both PRG registers''' $01 and $81 (and making shift and ANDs) _to compose_ the desired PRG page. Could someone clarify it? --[[User:Zepper|Zepper]] ([[User talk:Zepper|talk]]) 18:56, 24 September 2013 (MDT) | |||
Revision as of 00:56, 25 September 2013
Does this mapper use RAM at $6000-$7FFF? PRG RAM? Whatever? --Zepper (talk) 06:15, 18 September 2013 (MDT)
- It supports the same PRG RAM at $6000-$7FFF that the iNES format implies for most discrete mappers. There's no disable register, if that's what you meant. --Tepples (talk) 12:47, 18 September 2013 (MDT)
Are both the inner and outer PRG regs always used in PRG swaps? --Zepper (talk) 18:44, 21 September 2013 (MDT)
- Both registers are used to form the final 16K bank number unless you're in P=G=0 mode, in which case only the outer bank is used. But if you're just switching banks within one game, you're probably writing only to the inner PRG register. Let me make an analogy to a possibly more familiar mapper, MMC1: Consider the inner PRG register like $E000 and the outer like bit 4 of $A000 on SUROM/SXROM. --Tepples (talk) 12:57, 22 September 2013 (MDT)
Yes, but there's something weird for me. While the PRG diagram shows $8000-$BFFF to use R:01, _and_ $C000-$FFFF to use R:81, I think such PRG bank selection would be _separated_. Later, there's an info regarding ORing both PRG registers $01 and $81 (and making shift and ANDs) _to compose_ the desired PRG page. Could someone clarify it? --Zepper (talk) 18:56, 24 September 2013 (MDT)
